Tapped coil



April 2, 1957 E. c. HILL ET AL 2,787,769

TAPPED COIL Filed July 14-, 1953 may The/r A ttor/yy TAPPED COIL Ezra C.Hill and Harry J. Proxmire, Fort Wayne, Ind.,as-

signors to General Electric Company, a corporation of New YorkApplication July 14, 1953, Serial No. 367,858

6 Claims. (Cl. 336-492) This invention relates to coils for inductivedevices and more particularly coils having a tap.

In the design of inductive devices, such as transformers, it isfrequently necessary to provide a coil having a tap, i. e. a connectionbrought out intermediate the ends of the coil. When the coil is .a highvoltage coil and thus wound with fine wire, insulation problems havemade it difiicult to bring out a tap and therefore in the past, it hasbeen conventional practice to provide two separate coils with the endconnections between the two coils providing the tap.

It is therefore desirable that a coil construction be provided whichwill permit bringing out a tap therefrom without the necessity forsplitting the coil into two separate coils and further which willprovide an anchor for the lead attached to the coil tap.

It is therefore an object of this invention to provide an improvedtapped coil construction incorporating the desirable features set forthabove.

Further objects and advantages of this invention will become apparentand the invention will be better understood by reference to thefollowing description and the accompanying drawing, and the features ofnovelty which characterize this invention will be pointed out withparticularity in the claims annexed to and forming a part of thisspecification.

In accordance with this invention, a coil body is provided wound on aspool and having a plurality of layers of wire. One or more, preferablytwo axially extending tubular members are wound between two of the coillayers at or near the point where the tap is to be brought out. A tap istaken from the coil body and connected to one end of an external taplead. This connection is then positioned in one of the tubular membersand the external lead extends through the other of the tubular membersthereby anchoring the tap lead to the coil body.

In the drawing, Fig. 1 is a view in perspective, partially broken away,illustrating the improved tapped coil construction of this invention;and

Fig. 2 is a similar view illustrating the method of making the tappedconnection of Fig. 1.

Referring now to the drawing, there is shown a high voltage coil,generally identified as 1 having a plurality of layers 2 of relativelyfine wire wound on a spool 3. In order to provide for bringing out a tapfrom the coil 1, a pair of spaced apart axially extending tubularmembers 4 and 5, formed of suitable insulating material, are woundbetween two of the layers of the coil in the region from which the tapis to be brought out. These tubular members extend through substantiallythe entire axial length of the coil 1, as clearly shown in Figs. 1 and2. To form the tap, a single coil of wire is pulled away from theoutside of one of the layers forming a tap loop 6 as shown in Fig. 2.The tap loop 6 is connected to an end 7 of external tap lead 8 and thisconnection is then soldered, as at 9 in Fig. 1. The soldered connection9 together with the adjacent portions of the tap loop 6 and external taplead 8 are inserted in the tubular mem- United States P t O 2,787,769Patented Apr. 2, i957 her 4, as shown in Fig. 1. External tap lead 8 isthen brought through the other tubular member 5 with its other end 10being on the side of the coil 1 remote from the side from which the taploop 6 was taken. The finished coil may be bound together in anysuitable manner, as by tape 11 which may also anchor the other externalleads, one of which is shown at 12.

it will now be readily seen that this improved tapped coil constructionsecurely anchors the tap lead to the coil and that since all parts ofthe tap lead and coil loop are confined to the portion of the coil bodywhere the tap occurs, there are no points of high potential gradientbetween the tap lead and the coil as are created by conventional methodsof bringing out and anchoring tap leads. Here it will be seen that noreasonable amount of pulling on the end 10 of the tap lead 8 or ordinarymovement of lead will cause strain or breakage of the fine wire formingthe tap loop 6.

While the improved lead anchoring arrangement of this invention has beenshown in connection with a tap, it will be readily understood that itmay also be used for making end connections as well as for tapconnections. While two tubular members are shown, it will also bereadily understood that only one more than two may be utilized.

While we have shown and described a particular embodiment of thisinvention, further modifications and improvements will occur to thoseskilled in the art. We desire that it be understood therefore that thisinvention is not limited to the form shown and we intend in the appendedclaims to cover all modifications which do not depart from the spiritand scope of this invention.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A tapped coil comprising a coil body having a plurality of layers ofwire, a pair of axially extending tubular members formed of insulatingmaterial arranged between two of said coil body layers, said coil bodyhaving a tap taken from one side thereof, and an external tap lead, oneend of said tap lead being connected to said coil body tap, saidconnection being positioned in one of said tubular members, said taplead passing through the other of said tubular members and extendingfrom the side of said coil body opposite from said one side therebyanchoring said tap lead to said coil body.

2. A tapped coil comprising a coil body having a plurality of layers ofwire, a pair of axially extending tubular members formed of insulatingmaterial arranged between two of said layers, said coil body having atap taken from one side thereof, and an external tap lead, one end ofsaid tap lead being connected to said coil body tap, said connection andadjacent portions of said tap and tap lead being positioned in one ofsaid tubular members, said tap lead passing through the other of saidtubular members and extending from the side of said coil body oppositefrom said one side thereby anchoring said tap lead to said coil body.

3. A tapped coil comprising a coil body having a plurallity of layers ofwire, a pair of spaced apart axially extending tubular members formed ofinsulating material wound between two of said coil body layers, saidcoil body having a tap loop taken from one layer thereof on one side ofsaid coil body, and an external tap lead, one end of said tap lead beingconnected to said coil body tap loop, said connection and adjacentportions of said tap loop and said tap lead being inserted in one end ofone of said tubular members, said tap lead passing through the other ofsaid tubular members and extending from the side of said coil bodyopposite from said one side thereby anchoring said tap lead to said coilbody.

4. A tapped coil comprising a coil body wound on a spool and having aplurality of layers of relatively fine wire, a pair of axially extendingtubular members formed of insulating material wound between two of saidcoil body layers and extending through substantially the axial length ofsaid coil body, said coil body having a tap taken from one side thereof,and an external tap lead, one end of said tap lead being connected tosaid coil body tap, said connection and adjacent portions of said tapand tap lead being inserted in one end of one of said tubular members,said tap lead passing through the other of said tubular members andextending from the side of said coil body opposite from said one sidethereby anchoring said tap lead to said coil body.

5. A tapped coil comprising a coil body wound on a spool and having aplurality of layers of relatively fine wire, a pair of spaced apartaxially extending tubular members formed of insulating material woundbetween two of said coil body layers and extending through substantiallythe axial length of said coil body, said coil body having a tap looptaken from the outside coil of one layer thereof on one side of saidcoil body, and an external tap lead, one end of said tap lead beingconnected to said coil body tap loop, said conection and adjacentportions of said tap loop and said tap lead being positioned in one ofsaid tubular members, said tap lead passing through the other of saidtubular members and extending from the side of said coil body oppositefrom said one side thereby anchoring said tap lead to said coil body.

6. A coil comprising a coil body having a plurality of layers of wire, apair of axially extending tubular members formed of insulating materialarranged btween two of said coil body layers, said coil body having alead taken from one side thereof, and an external lead, one end of saidexternal lead being connected to said coil lead, said connection beingpositioned in one of said tubular members, said external lead passingthrough the other of said tubular members and extending from the side ofsaid coil body opposite from said one side thereby anchoring saidexternal lead to said coil body.

References Cited in the file of this patent UNITED STATES PATENTS

